10 valvular heart disease (pathology) Flashcards
What are the major causes of valvular disease?
- congenital (most common= bicuspid aortic valve)
- acquired
- aortic stenosis (senile calcification)
- aortic insufficiency (dilation of ascending aorta related to HTN and aging)
- mitral stenosis (rheumatic heart disease)
- mitral insufficiency (myxomatous degeneration)
- stenosis more frequent than insufficiencies
Describe dystrophic calcification
- damage caused by wear and tear complicated by deposits of calcium phosphate
- distinct from atherosclerosis but shares risk factors (hyperlipidemia, HTN, inflammation)
- e.g. calcific aortic stenosis, mitral annular calcification
What is the most common valvular abnormality?
Calcific aortic stenosis
Describe calcific aortic stenosis
- most common in “senile” valves; 8th/9th decade
- presents earlier (5th/6th decade) in bicuspid and unicuspid valves; esp with the notch mutation
- clinical effects:
- increased pressure= LV hypertrophy
- angina, ischemia, CHF (50% with CHF die within 2 years)
- syncope
- treatment= valve replacement
Grossly, describe calcific aortic stenosis
- heaped up calcified masses in cusps primarily at the bases
- free cuspal edges not involved
- no fusion of commisures
Describe mitral annular calcification
- degenerative calcific deposits on fibrous ring, at the base of the valve that usually does not affect valve function
- calcifications= sites for thrombi/infection
- women >60 yo
- increased in patients with myxomatous (degenerative) valves or elevated LV pressure
Describe myxomatous degeneration of the mitral valve
- aka mitral valve prolapse
- one or both leaflets enlarged, hooded, redundant, floppy (myxoid)
- prolapses/balloons back into left atrium during systole
- very common (3% of adults), esp in young women
- feature of marfan syndrome
- usually no serious complications
- hear a midsystolic click on auscultation
What is the most important complication of rheumatic fever?
Progression to chronic valvular dysfunction (mitral stenosis)
Describe the pathophysiology of rheumatic fever
- occurs following an episode of group A strep (pyogenes) pharyngitis
- immunologically mediated (Ab against M protein cross react with glycoprotein antigens in heart, joints, and other tisues
- acute, multisystem, inflammatory disease with major cardiac manifestations
Describe the morphology of rheumatic fever
- widely disseminated inflammatory lesions found in many sites
- pancarditis (affects all layers)
- bread and butter pericarditis
- myocarditis (Aschoff bodies)
- endocardium/ left sided valves with fibrinoid necrosis and verrucae
- subendocardial (MacCallum) plaques
What is an Aschoff body?
- the classic lesion of acute rheumatic fever
- foci of swollen eosinophilic collagen surrounded by T lymphocytes, plasma cells and plump macrophages
- anitschkow cells, caterpillar cells
What are the major complications of chronic rheumatic heart disease?
Organization of inflammation and fibrosis leads to…
- thickened valve leaflets
- fusion of commissures (fishmouth/buttonhole deformities)
- fusion/thickening of chordae tendinae
**Major effect is mitral stenosis
(also aortic>tricuspid>>pulmonary involvement)
What are the consequences of mitral stenosis?
- leads to L atrial dilation (sometimes thrombus formation)
- reduces cardiac output (mechanical obstruction prevents filling of LV)
- result= pulmonary congestion, eventual right ventricular hypertrophy and right sided heart failure
Describe the JONES criteria
The major manifestations of rheumatic fever:
- joints (migratory polyarthritis)
- heart (pericardial rub, weak heart sounds, tachycardia, arrhythmia)
- nodules (subcutaneous on extensor surfaces)
- erythema marginatum
- sydenham chorea
What are some minor manifestations of rheumatic fever?
- fever
- arthralgia
- elevated acute phase reactants
Describe nonbacterial thrombotic endocarditis
- depositions of small masses of fibrin, platelets, and other blood products on leaflets (along the lines of closure)
- not destructive or inflammatory
- often in debilitated patients (cancer, sepsis), and may result in emboli and infarcts
Describe Libman-Sacks endocarditis
- most characteristic cardiac manifestation of the autoimmune disease systemic lupus erythematosus
- mitral/tricuspid involvement
- antiphospholipid antibodies present
- either or both sides of leaflets (may also be on endocardium)
- may have intense inflammation
Describe the locations of the 4 types of vegetative endocarditis we discussed
- Rheumatic Heart Disease
- mitral usually (sometime +aortic)
- inflammation and fibrosis
- Infectious Endocarditis
- mitral and aortic most common
- Non-Bacterial Thrombotic Endocarditis
- any valve (small along closure)
- sterile, nondestructive, noninflammatory
- Libman-Sacks Endocarditis
- mitral and tricuspid
- both sides of leaflets
Describe carcinoid syndrome
- flushing, cramps, nausea, vomiting, diarrhea
- from carcinoid tumor producing serotonin, kallikrein, bradykinin, histamine, prostaglandins, and tachykinins
- serotonin and bradykinin in activated by…
- MAO in pulmonary vasculature
- passage through liver
- serotonin and bradykinin in activated by…
- 50% of pts with carcinoid syndrome have plaque-like fibrosis of right-heart endocardium and valves
- tricuspid insufficiency
- pulmonic stenosis
